Firestore Query: unsupported FieldFilter value type: 6

It looks like that Firestore has a bug at the moment that I just reproduced in my test app with firestore-react.
Firestore Issue:
https://github.com/GoogleCloudPlatform/google-cloud-java/issues/2816

Demo: (try uncommenting the rest of the line #20) .where('createdBy', '==', userKey)
https://codesandbox.io/s/0x3m4lnxwn

You might want to restrict your firebase NPM version to last working one (I don't know which one it is) or make a fallback to .get() as suggested in the original issue.

Or I might have just messed up :-D

Cheers :)